In display systems, such as digital light processor (DLP) systems and liquid crystal display (LCD) systems, it is often desirable to include information in displayed images that is usable by the display system or another electronic device. With many display systems, however, information that is added into displayed images for use by display systems may be seen by a viewer. The information may detract from the viewer's enjoyment of the displayed images. It would be desirable to be able to include information in visual images formed by a display system where the information is imperceptible by a viewer.